Joining table using PXSelectJoin using cast in BQL statement - acumatica

Question

I have a requirement to write a BQL statement for below SQL query
SELECT * FROM CSATTRIBUTEGROUP INNER JOIN INVENTORYITEM ON CSATTRIBUTEGROUP.ENTITYCLASSID=CAST(INVENTORYITEM.ITEMCLASSID AS NVARCHAR(10))
LEFT JOIN CSANSWERS ON INVENTORYITEM.NOTEID=CSANSWERS.REFNOTEID WHERE INVENTORYCD='CPU'
The EntityClassID in CSAttribute & ItemClassID in inventory are different type. How to join the table using BQL.

Answer 1

One would be tempted to create a custom view representing the INVENTORYITEM table with a cast of ITEMCLASSID. However custom views are not recommended. Instead try creating a PXProjection to represent the INVENTORYITEM table as usrINVENTORYITEM. Then use a PXString to convert the Int? to a string. Once exposed you can work out your BQL as shown below.
#region InventoryItem - projection
[PXProjection(typeof(Select<InventoryItem>), Persistent = false)]
public partial class usrInventoryItem : InventoryItem
{
#region ItemClassIDStr
[PXString(10, IsUnicode = true)]
[PXUIField(DisplayName = "ItemClassIDStr", Visibility = PXUIVisibility.SelectorVisible)]
public virtual string ItemClassIDStr
{
get
{
return $"{ItemClassID}";
}
set
{
this.ItemClassIDStr = value;
}
}
public abstract class itemClassIDStr : IBqlField { }
#endregion
}
#endregion
then the BQL statement:
// basic example of your join.
public PXSelectJoin<CSAttributeGroup, LeftJoin<usrInventoryItem,
On<usrInventoryItem.itemClassIDStr, Equal<CSAttributeGroup.entityClassID>>>> ExampleJoin;